Service Guide 4-3

4.2.5 Keyboard Subsystem

The keyboard subsystem, implemented on the Keyboard Assembly and the Motherboard
Assemblies Board, consists of the following major sections:
Keyboard Assembly
Keyboard Scanner
Status LED Interface

4.2.6 Hard Disk Drive Subsystem

The Hard Disk Drive Subsystem, implemented on the Motherboard Board and on the associated
hard disk drive module(s), provides disk storage for all system software and user files.
The notebook is equipped with an 1.6 GB or larger hard disk drive. The hard disk drive also
features built-in power conservation features configured from the standard CMOS Setup Routine. An
Automatic Power Down mode can be selected which powers down the drive motor during periods of
inactivity. An additional level of power conservation may also be selected which powers down the
motor plus all control circuits.
The hard disk drives are factory formatted as a single drive (Drive C:) and are preloaded with
installation versions of Windows 95, Windows NT or Windows for Workgroups.
4.2.6.1 Hard Disk Drive Power Management
Both the internal hard disk drive and the hard disk drive installed in the media bay implement power
savings features. From the CMOS setup routine, an automatic power down mode can be selected
which enables the drive to turn off its motor after a specified period of inactivity. Additional Sleep
modes can direct additional power savings during inactive periods by powering down the control
circuitry.

4.2.7 Floppy Disk Drive Subsystem

The Extensa 67x Series notebooks contain provisions for supporting a Floppy Disk Drive installed
internally or externally connected to the parallel port. The Floppy Disk Drive Subsystem consists of a
Floppy Controller and the Floppy Disk Drive located either in the media bay or external to the
notebook (not both).
The 3.5-inch floppy disk drive can read/write standard 3.5-inch disks (either1.44 MB or 2 MB
capacity). The drive can also read a 720 KB disk (for interchange of data with other computers).
The data transfer rate for the floppy disk drive is 500 Kbits per second for high-density disks and 250
Kbits per second for double-density disks.

4.2.8 Power Subsystem

The notebook is equipped with a software/hardware monitored/controlled Power Subsystem that
minimizes battery usage for prolonged battery operation and automatically recharges the batteries
when the notebook is used with an AC adapter.